Cyclododecatriene-1, 5, 9 process



United States Patent 3,331,047 CYCLODODECATRlENE-1,5,9 PROCESS HerbertSousa Eleuterio and Theodore Augur Koch, Wilmington, DeL, assignors toE. I. du Pont de Nernours and Company, Wilmington, Del., a corporationof Delaware No Drawing. Continuation-impart of application Ser. No.485,090, Sept. 3, 1965. This application Dec. 7, 1965, Ser. No. 59?,721

8 laims. (Cl. 260-666) ABSTRACT OF THE DTSCLGSURE Aliphatic carboxylicacids are employed to increase the rate and yield in the trimerizationof butadiene to form cyclododecatrienel,5,9 using organoaluminumsesquichloride and titanium compounds as catalysts.

This application is a continuation-in-part of copending application Ser.No. 485,090, filed Sept. 3, 1965 by H. S. Eleuterio and T. A. Koch, nowabandoned.

The present invention relates to a process for the trimerization ofbutadiene to cyclododecatriene-(1,5,9) using a catalyst prepared from anorganoaluminum sesquihalide, an aliphatic acid and a selectedtetravalent titanium compound.

The production of cyclododecatriene-(1,5,9) by subjecting 'butadiene tothe action of various catalysts is known. Butadiene trimerizationcatalysts, based on alkylaluminum chlorides and titanium halides, suchas those described in Schneider et al., United States Patent 3,076,-045, and Wilke, United States Patent 2,964,574 are known.

The present invention is an improvement both in rate of reaction and inultimate yield over these above-mentioned prior processes involving theuse of a certain catalyst system under certain reaction conditions.

The catalyst system is prepared from the hereinafter definedorganoaluminum sesquichloride, an aliphatic acid and titaniumtetrachloride. Catalyst components are preferably limited to thesethree. For convenience, the exact composition of the organometalliccompound may be varied and described as any composition having thefollowing ratio of materials wherein Z is selected from the classconsisting of alkyl radicals having 2-3 carbon atoms and the phenylradical. When the process is conducted at about 1 p.s.i.g. pressure, themolar ratio of organoaluminum sesquichloride to the aforesaid acidshould be maintained at from 1/0.l mole to l/ 0.50 mole with from 1/0.3to 1/ 0.4 being especially the preferred range. As the pressure isincreased above 1 p.s.i.g., the above ranges can be expanded, e.g., from1/0.1 to 1/0.7 or greater.

The tetravalent titanium compounds which are operable in the presentprocess are soluble in the reaction medium to the extent of at least0.01 mole percent based upon cyclododecatriene at 20 C. and do notcontain a substituent which inactivates the catalyst. These titaniumcompounds have the formula TiA, wherein A is selected from the classconsisting of chlorine, bromine, iodine and OR, wherein R is ahydrocarbon radical having 1-20 carbon atoms. The four As in a giventitanium compound may be the same or different.

Acids which are operable in the present invention are selected from theclass consisting of formic acid, oxalic acid, and aliphatic acids having2-15 carbon atoms, aliphatic acids having 2-15 carbon atoms which aresub- 3,381,047 Patented Apr. 30, 1968 stituted with groups selected fromthe class consisting of alkyls having 1-6 carbon atoms, phenyl, andalkyl substituted phenyl having 7-12 carbon atoms and wherein at least 1alpha carbon atom in the main chain of said aliphatic and substitutedaliphatic acids has at least one and preferably at least two hydrogenatoms attached thereto. Other substituents on the acid that do notadversely affeet the catalyst or the yield to the desired products arewithin the purview of this invention, e.g., acids having halogensubstituents sufficiently removed from the carboxyl groups are operable.Illustrations of the acids contemplated by the above definition aresaturated and unsaturated, mono-, di-, and tricarboxylic acids such asformic; propionic; butyric; lauric; pentadecanoic; acrylic; crotonic;sorbic; nonanoic; 3-hexyl-; decanoic, 4-butyl-; crotonic, 3-methyl-;2,5-heptadienedioic, 4-pentyl-; 1,2,4- hexanetricarboxylic;3-hexynedioic; 4,6-decadiynedioic; pentyn-4-oic acid; capric;pelargonic; isobutyric; isovaleric; oxalic; malonic; pimelic; sebacic;azelaic; isocaproic; isoenanthic; succinic; glutaric; adipic;1,12-dodecanedioic; and u,5-dimethy'l-butyric acid. Formic and aceticacids are preferred.

The ratio of organoaluminum sesquichloride to the titanium compound isnot so critical. The molar ratio of ethylaluminum sesquichloride totitanium tetrachloride may be varied from 3/1 to 30/1. Higher ratios maybe used but are not desirable because of the expense of theethylaluminum sesquichloride.

The catalyst may be made up by reacting the acid with ethylalurninumsesquichloride followed by reaction of the product so formed withtitanium tetrachloride. However, for continuous operation, it isconvenient to add all three catalyst components separately andsimulaneously to the reaction vessel.

The butadiene trimerization reaction can be run in any inert hydrocarbonsolvent such as benzene, cyclohexane, toluene, xylene and hexane.Cyclododecatriene is an excellent solvent and the preferred one forcontinuous trimerization of butadiene.

The butadiene trimerization reaction temperature should be maintained atfrom 20 to C., and pref erably from 60 to 90 C. At lower temperatures,the reaction rates become unduly slow and at higher temperatures,increasing yield losses to by-products occur.

Pressure is not a critical variable in the instant invention and may bevaried from /2 atm. to 50 atm., preferably at from 1 to 5 atm.Increasing the pressure in many cases will improve the productivity ofthe catalyst.

By operating within the hereinabove set forth limits, butadiene trimeris formed at above the average reaction rates in the absence of an acidand in yields usually greater than 80 percent. The reaction can beconducted in multiple stages.

The following examples are illustrative of the invention.

Examples 1-7 The apparatus employed for the trimerization consists of a2 liter, 3-necked, creased, round-bottomed flask fitted with rubberstopper, condenser with outlet to mercury bubbler, thermometer, highspeed stirrer, and gas inlet. After the apparatus is well dried andflushed with inert gas, ml. of benzene which is dried and renderedoxygen-free by distillation from sodium potassium alloy under nitrogenis added to the flask. The benzene is heated to 55 C.i-5 C. and aceticacid as a 0.4 M solution in benzene and a 1 M solution of ethyl aluminumsesquichloride in benzene in the amounts indicated in Table I isinjected with moderate agitation followed by 1 millimole of titaniumtetrachloride as 10 ml. of a 0.1 M solution in benzene. The rate ofstirring is then increased to 2000 rpm. Butadiene, purified by stirringwith and distillation from tn'isobutyl aluminum, is passed into thereactor slightly more rapidly than it is adsorbed to maintain a purge ofa few cc./min. through the trap The reaction temperature is maintainedat 70: 2 C. After the time shown in the table, the catalyst isdeactivated with a 10 ml. sample of a 1:1 mixture of acetone andisopropyl alcohol and a sample of the crude reaction mixture is analyzedimmediately by gas chromatography. The average rate of the reactionthroughout a run is given as the number of g./ min. of purecyclododecatriene actually produced. Example 7 illustrates the poor rateand yield obtained in the absence of the acid.

The optimum ratio of et-hylaluminum sesquichloride to acetic acid asshown by the above data is about 1/0.4.

Example 8 A 500 cc. reaction vessel is equipped with inlets forcontinuous introduction of the solutions of the cataylst componentssubstantially as described in Paragraph 1 of Examples 1-7 and drybutadiene. Liquid product is continuously removed such that steady stateconditions prevail. The conditions and results are reported in Table II.

TABLE II Example 8:

Catalyst ratio moles Et3A12C13/TIC14/ acetic acid 10/ 1/4.0

Steady state productivity pounds crude/ Temperature, C. 75 Pressure,p.s.i.g 1 Percent distribution in crude:

Cyclododecatriene 87.7 Cyclooctadiene 0.74 Vinylcyclo-hexane 1.08Polymer 8.67

Examples 9-27 A 500 cc. reaction vessel is equipped with inlets for thecontinuous introduction of the solution of the catalyst and butadienewhich is dried in the liquid phase with a molecular sieve and isintroduced as a gas by vaporizing in the presence of tri-n-butylaluminum. The inlets are arranged to permit the introduction ofethylaluminum sesquichloride (except Example 21 which uses phenylaluminum sesquicliloride), the titanium compound and the acid isseparate streams. As in Example 8, a liquid product is continuouslyremoved such that a steady state condition prevails. The runs arestarted by filling the reactor with dry cyclododecatriene and suflicientcatalyst for one hour of operation. Butadiene gas is introduced inamounts sufiicient to maintain 1 p.s.i.g. durin the run (except Examples22-27 which were conducted at 5 p.s.i.g.). The reaction is conducted at75 C. Except where indicated, the titanium compounds are added as asolution in cyclohexane and at the rate of 1.01 g. of titaniumtetrachloride per gallon per hour or the equivalent thereof. The adipicand dodecanedioic acids were prereacted with the sesquichloride intoluene while maintaining a local excess of the sesquichloride in orderto obtain a clear solution. The dicarboxylic acids are insolubleinitially but go into solution as their reaction with the sesquichlorideprogresses. For adipic, to 200 cc. of toluene was added 3.65 grams ofadipic acid and 31.67 grams of the sesquichloride; for dodecanedioic, to200 cc. of toluene were added 5.76

gal of crude 1n reactor/hour 7.17 grams of dodecanecnoic and 32.2 gramsof the sesqui- Feed rate T1C1 gm./gal./hour 1.0 4 chloride. Theprereaeted mixture was then added to the Steady state T1Cl conc. gramT1C1 reactor. The composition of the product along with the gal. 1.0other experimental results are shown 1.11 Table III.

TAB LE III Catalyst:

Molar Ratio 10/1/5 10/1/4 loll/3.-.- 10/1/2 10/1/3 10/1/4... 10/1/3.5loll/3.5.- 10/1/5 10/1/4 10/1/1.96

(CzH5)3AlzC13/TiA4/A0id. A 01- Cl" Cl- Cl- Cl- Isopropoxrdek I Cl- C-l-Cl- Acid Acetic Formic Fo Forrnic 7 Formirfl. Formic LauricL Adipic.Steady State Productltity. 6.05 5.80 7.96--- 7.81.-- 7.73 5.2 4.00-.5.34""- 4.06.

(Pounds of crude/gal. of crude in reactor/hour). Product Distribution inCrude Product:

Cyclododecatriene 84.6-.- 85.8 82.5"..- 73.9... 85.9 82.8.Cyclooctadienc 1.17 .50 1.00 1.32 0.63. Vinyl Cyclohexane 1.15.. .68.-..37.-." 0.99 3.87. Nonvolatile residue 10.l. 8.56""- 8.09"- 7.99 .226.7- 10.7--- 10.8.

Catalyst:

Molar Ratio loll/1.92 10/1/4 10/1/4.--.. 10/1/4--- 10/1/4 10/1/4 10/1/410/1/4.

(CzHs)aAIzCh/TiAdacid. Cl- Br- 01* 01* CI- 01-. Acid Dodecanedioic.-For-mic Phenyl acetic 10-un' Acrylic Isobutyriefi decenoic Steady StateProductivity: 4.38 6.78 8.28-"-.. 4.81 7.05 6.37 6.88 3.59.

(Pounds of crude/gal. of crude in reactor/hour). Product Distribution inCrude Product:

Cyclododeeatriene 84.2 88.0 85.9- 85.0 82.3. Cyclooctadiene 0.54. 1 0Vinyl cycl0hexane 3.49 Nonvolatile residue--. 9.86 13.4

1 Added as 2.71 M in cyclohexane.

1 vaporized and added with the dry butadiene.

3 Added as 0.298 M in cyclohexane.

4 Added as 0.015 M in cyclohexane (somewhat unstable in solution).

B The catalyst was phenylaluminum sesquichloride added as a by weightsolution in clilorobcnzone.

6 Normalized.

7 Added as 1.59 Min benzene.

X Added as 0.681 M in benzene.

9 Added as 1.30 M in benzene.

Added as 1.86 M in benzene.

Operation at 5 p.s.i.g.

12 Added as 1.99 M in cyclohexane. 13 Added as 0.458 M in cyclohexane.14 Added as 0.415 M in benzene.

15 Added as 1.05 M in cyclohexane. Added as 2.98 M in cyclohexanc. 17Added as 2.17 M in cycloliexane.

Cycloclodecatriene is a valuable chemical intermediate which can bereadily oxidized to succinic acid which is useful in the production ofplastics such as polyamides. It also may be hydrogenated in a knownmanner. Thus, cyclododecene or cyclododecane is obtained fromcyclododecatriene. These hydrogenated products may, in turn, be oxidizedin known manner to form the corresponding dicarboxylic acids.

We claim:

1. A process for the production of cyclododecatriene- 1,5,9 whichcomprises contacting butadiene with a catalyst system formed by mixingan organoaluminum compound having the formula wherein Z is selected fromthe class consisting of alkyl radicals having 2 to 3 carbon atoms andthe phenyl radical with from about 0.10 to about 0.70 mole of analiphatic carboxylic acid having 1 to carbon atoms and a titaniumcompound having the formula TiA, where A is selected from the classconsisting of chlorine, bromine, iodine and OR, where R is a hydrocarbonradical having 1 to carbon atoms, in an amount such that the molar ratioof said organoaluminum compound to said titanium compound is maintainedat from 3-30/1 and at a temperature in the range of 20 to 120 C. and ata pressure of 0.5 atmospheres.

2. The process of claim 1 wherein said orgauoaluminum compound isethylaluminum sesquichloride.

3. The process of claim 2 conducted in the range to C.

4. A process for the preparation of cyclododccatriene- 1,5,9 whichcomprises contacting butadiene with a catalyst consisting essentially ofethylaluminum sesquichloride from 0.20 to 0.40 mole per mole of saidsesquichloride of an aliphatic monocarboxylic acid having 1 to 10 carbonatoms and titanium tetrachloride in an amount such that the molar ratioof said sesquichloride to titanium tetrachloride is maintained at from3-30/ 1 at a temperature of 60 to 90 C. and at a pressure of 0.5-50atmospheres.

5. The process of claim 1 wherein said acid is acetic acid.

6. The process of claim 1 wherein said acid is formic acid.

7. The process of claim 4 wherein said acid is acetic acid.

8. The process of claim 4 wherein said acid is formic acid.

References Cited UNITED STATES PATENTS 3,163,611 12/1964 Anderson et al252429 3,280,205 10/1966 Yosida et al. 260-666 DELBERT E. GANTZ, PrimaryExaminer.

V. OKEEFE, Assistant Examiner.

